Equity Incentive Plan (Tables)

12 Months Ended

Dec. 31, 2015

Equity Incentive Plan

Schedule of stock option activity

	Number of Shares Subject to Option			Weighted Average Exercise Price		Weighted Average Remaining Contractual Term	Aggregate Intrinsic Value
Options outstanding, December 31, 2012		1,017,195		$	17.25	8.2 years	$10.6 million
Granted		209,268			32.50
Exercised		(54,781	)		16.86		$1.0 million
Forfeited		(37,232	)		23.00
Expired		(535	)		34.82
Options outstanding, December 31, 2013		1,133,915		$	19.89	7.6 years	$14.0 million
Granted		—			—
Exercised		(307,022	)		16.10		$5.6 million
Forfeited		(64,851	)		25.83
Expired		(3,947	)		15.80
Options outstanding, December 31, 2014		758,095		$	20.94	6.7 years	$13.7 million
Granted		—			—
Exercised		(410,322	)		20.15		$12.0 million
Forfeited		(7,281	)		27.53
Expired		(282	)		15.23
Options outstanding, December 31, 2015		340,210		$	21.77	5.8 years	$11.9 million
Exercisable at December 31,
2013		498,176		$	16.51	7.1 years	$7.8 million
2014		474,132		$	18.78	6.4 years	$9.6 million
2015		234,943		$	18.47	5.4 years	$9.0 million

Schedule of unvested shares subject to options

	Number of Shares Subject to Option			Weighted Average Fair Value at Grant Date
Unvested balance, December 31, 2012		730,159		$	5.70
Granted		209,268			10.01
Forfeited		(37,232	)		7.21
Vested		(266,456	)		5.54
Unvested balance, December 31, 2013		635,739		$	7.10
Granted		—			—
Forfeited		(64,851	)		8.03
Vested		(286,924	)		6.25
Unvested balance, December 31, 2014		283,964		$	7.75
Granted		—			—
Forfeited		(7,281	)		8.48
Vested		(171,416	)		6.86
Unvested balance, December 31, 2015		105,267		$	9.13

Schedule of assumptions used to value the stock options granted

	2013
Expected term (in years)		6.25
Expected volatility		43.86	%
Expected annual dividend		3.33	%
Risk-free rate		1.26	%

Schedule of restricted awards and RSUs

	Restricted Awards and Units			Weighted Average Fair Value at Grant Date
Unvested balance, December 31, 2012		598,695		$	21.37
Granted		194,302			32.43
Forfeited		(58,199	)		28.44
Vested		(239,647	)		20.96
Unvested balance, December 31, 2013		495,151		$	25.08
Granted		216,175			31.51
Forfeited		(109,798	)		27.64
Vested		(207,512	)		22.79
Unvested balance, December 31, 2014		394,016		$	29.10
Granted		187,644			47.41
Forfeited		(34,788	)		36.06
Vested		(169,260	)		26.96
Unvested balance, December 31, 2015		377,612		$	38.51

Summary of assumptions used to value performance stock awards

	2015			2014
Expected term (in years)		2.83			2.83
Expected volatility		25.51	%		32.98	%
Expected annual dividend		—			—
Risk-free rate		1.02	%		0.64	%